Iridium oxide-coated defibrillation electrode: reduced shock polarization and improved defibrillation efficacy

BACKGROUND: Transvenous implantable cardioverter-defibrillator (ICD) leads are designed to deliver electric shocks to the heart for termination of ventricular dysrhythmias. However, the efficiency of different lead materials has not been well studied. This study compares an ICD lead coated with iridium oxide (IROX), a material that reduces shock-induced polarization, with an otherwise identical, uncoated lead. METHODS AND RESULTS: The defibrillation threshold (DFT) was determined in 13 swine with both IROX-coated and uncoated ICD leads paired with an uncoated "can" electrode. The leads were exchanged through a Teflon sheath to reproduce the intracardiac position. The delivered energy DFT of the IROX-coated lead was 15.9+/-5.4 J and was significantly lower than the delivered energy DFT of the uncoated lead (19.1+/-5.1 J; P<.006). The initial lead impedance was equivalent in both leads (IROX, 41.7+/-5.8 omega; uncoated, 41.3+/-4.7 omega; P=NS) at DFT. However, the impedance rose by 7.3+/-2.0 omega during the first phase and by 3.7+/-2 omega during the second phase with the uncoated lead, whereas the corresponding impedance change was 1.0+/-0.3 omega during phase 1 and 1.6+/-0.5 omega during phase 2 (P<.01 each phase) when the IROX-coated lead was used. CONCLUSIONS: This study shows that an IROX coating of this lead system significantly lowers the DFT energy in the swine model. The blunting of the impedance rise by the IROX coating that is seen is consistent with a reduction in electrode polarization.     

Epidural anaesthesia for caesarean delivery in triple and quadruple pregnancies

BACKGROUND: Mechanical and/or hormonal factors may increase the spread of epidural anaesthesia in pregnancy, and hormonal changes are more pronounced in high-order pregnancies. However, no previous study has evaluated the dose requirements and haemodynamic effects of epidural anaesthesia for caesarean delivery in this latter situation. METHODS: The anaesthetic requirements to obtain a T4 upper sensory level were retrospectively compared in triple (n = 19) or quadruple (n = 2) pregnancies to 31 singleton pregnancies who received epidural anaesthesia for elective caesarean delivery using 2% lidocaine with 1/200,000 adrenaline. RESULTS: In high-order pregnancies, the gestational age at delivery was lower than in singleton pregnancies (34.9 +/- 1.9 weeks vs 38.2 +/- 1.1 weeks; P = 0.0001) whereas maternal body weight (76.5 +/- 8.7 kg vs 73.4 +/- 14.8 kg; NS) and lidocaine requirements (428 +/- 95 mg vs 426 +/- 98 mg; NS) were similar. Moreover, although the overall incidence of hypotension was not different (multiple pregnancy; 65% vs 58% in singletons), ephedrine (5.4 +/- 5.3 mg vs 10.7 +/- 13.8 mg; P < 0.05) and additional fluid requirements during onset of the block (4.3 +/- 1.7 mL/kg vs 5.3 +/- 2.6 mL/kg; P = 0.03) were less than in singletons. CONCLUSION: We found surprisingly similar anaesthetic requirements for epidural anaesthesia in high-order and singleton pregnancies. Mechanical factors may have played an important role. Moreover, the need for ephedrine and fluids was less in high-order pregnancies. This could be related to more pronounced physiological changes or to different physician attitudes.     

The interaction between spherical particles and triple lines and quadruple points

The interaction force between a spherical, incoherent particle and a triple line or a quadruple point in a polycrystalline structure is calculated. The effect of such particles on grain growth stagnation is then calculated when the interaction force between particles, and grain boundaries, triple lines and quadruple points contribute to the stagnation. The results of the calculation compare very well with results obtained by computer simulations of the stagnation process and also with earlier estimates.     

Effect of a single element subcutaneous array electrode added to a transvenous electrode configuration on the defibrillation field and the defibrillation threshold

Even with the use of biphasic shocks, up to 5% of patients need an additional subcutaneous lead to obtain a defibrillation safety margin of at least 10 J. The number of patients requiring additional subcutaneous leads may even increase, because recent generation devices have a < 34 J maximum output in order to decrease their size. In 20 consecutive patients, a single element subcutaneous array lead was implanted in addition to a transvenous lead system consisting of a right ventricular (RV) and a vena cava superior lead using a single infraclavicular incision. The RV lead acted as the cathode; the subcutaneous lead and the lead in the subclavian vein acted as the anode. The biphasic defibrillation threshold was determined using a binary search protocol. Patients were randomized as to whether to start them with the transvenous lead configuration or the combination of the transvenous lead and the subcutaneous lead. In addition, a simplified assessment of the defibrillation field was performed by determining the interelectrode area for the transvenous lead only and the transvenous lead in combination with the subcutaneous lead from a biplane chest X ray. The intraoperative defibrillation threshold was reconfirmed after 1 week, after 3 months, and after 12 months. The mean defibrillation threshold with the additional subcutaneous lead was significantly (P = 0.0001) lower (5.7 +/- 2.9 J) than for the transvenous lead system (9.5 +/- 4.6 J). With the subcutaneous lead, the impedance of the high voltage circuit decreased from 48.9 +/- 7.4 omega to 39.2 +/- 5.0 omega. In the frontal plane, the interelectrode area increased by 11.3% +/- 5.5% (P < 0.0001) and in the lateral plane by 29.5% +/- 12.4% (P < 0.0001). The defibrillation threshold did not increase during follow-up. Complications with the subcutaneous electrode were not observed during a follow-up of 15.8 +/- 2 months. The single finger array lead is useful in order to lower the defibrillation threshold and can be used in order to lower the defibrillation threshold.     

A comparison of transthoracic impedance using standard defibrillation paddles and self-adhesive defibrillation pads

Because of the typical metaphyseal-epiphyseal growth of giant cell tumors and chondroblastomas, the optimal result of an en bloc resection can usually only be achieved by a loss of joint function. For this reason, intralesional excision has prevailed, though it leads to a high rate of relapses. Adjuvant therapy involving irrigation of the remaining bone cavity with phenol can distinctly decrease the rate of relapse. Little is known about the amount of phenol applied that is absorbed. This study investigated the urinary excretion of phenol following the instillation of 102 ml of a 5% phenol solution. The method consisted of urine collection from 11 patients treated by phenol instillation preoperatively, and at 1, 3, 6, 12 and 24 h postoperatively. The urine specimens were analysed for phenol by mass spectrometry. Preoperatively, the value was 5.1 mg/l on average. The maximum concentration of 62 mg/l was found 1 h after instillation, with an average value of 41.5 mg/l, and after 3 h of 18.9 mg/l. A further rapid decrease in the excretion rate was recorded, with normal values being reached after 12 h. This means a maximum of 9% and an average of 2% of the instilled amount of phenol were excreted in the urine within 24 h postoperatively. By comparing these urinary concentrations to published standards, we conclude that the instillation of a 5% phenol solution into bony lesions is associated with a relatively low risk of systemic toxicity.     

Importance of electrode conductive surface area and edge effects on ventricular defibrillation efficacy

INTRODUCTION: The role of edge effects and electrode surface area of the right ventricular (RV) transvenous lead (TVL) on defibrillation efficacy is unknown. METHODS AND RESULTS: Defibrillation threshold (DFT) testing was conducted randomly in 12 dogs using ring electrode leads in an RV/SVC (superior vena cava) or RV/SVC/patch system. The leads (RV-4, RV-8t, RV-8, RV-15) had electrode surface areas of 20%, 20%, 40%, and 70%, respectively. A computer model predicted the magnitude of electrode surface current (RV-8t > RV-4 > RV-8 > RV-15) and the potential distribution (PD) at four sites: electrode surface (site a) and at 2 mm (b), 4 mm (c), and 8 mm (d) away from the surface. Despite different near-field PDs (sites a, b, c), PDs were nearly identical at site d. Resistance decreased as the surface area increased. DFT energy for the RV-15 lead was lower than the RV-4 and RV-8t. There was no difference between energy requirements for the RV-15 and RV-8 leads. No difference was found in DFT current for each lead. Comparison of the RV-8t and RV-4 leads showed no difference in DFT energy despite a lower resistance and a greater number of edges. CONCLUSIONS: Increasing the RV TVL surface area lowered the resistance. However, surface area coverages > or = 40% did not lower DFT energy. No significant change in DFT current occurred despite different predicted near-field current densities. PDs were nearly identical 8 mm from the electrode surface. Thus, the far-field current density appears to play a more important role in determining defibrillation success.     

A triple dissociation of memory systems: Hippocampus, amygdala, and dorsal striatum.

Investigated the respective roles of the hippocampus (H), the amygdala (A), and the dorsal striatum (DS) in learning and memory. A standard set of experimental conditions for studying the effects of lesions to the 3 brain areas using an 8-arm radial maze was used: a win-shift (W-SH) version, a conditioned cue preference (CCP) version, and a win-stay (W-ST) version. Damage to the hippocampal system impaired acquisition of the W-SH task but not the CCP or W-ST tasks. Damage to the lateral A impaired acquisition of the CCP task but not the W-SH or W-ST tasks. Damage to the DS impaired acquisition of the W-ST task but not the W-SH or CCP tasks. Results are consistent with the hypothesis that the mammalian brain may be capable of acquiring different kinds of information with different, more-or-less independent neural systems (NSs). A NS that includes the H may acquire information about the relationships among stimuli and events. An NS that includes the A may mediate the rapid acquisition of behaviors based on biologically significant events with affective properties. An NS that includes the DS may mediate the formation of reinforced stimulus–response associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical shock tolerability and effect of different right atrial electrode locations on efficacy of low energy human transvenous atrial defibrillation using an implantable lead system

OBJECTIVES: The objectives of this study were 1) to evaluate the effect of different right atrial electrode locations on the efficacy of low energy transvenous defibrillation with an implantable lead system; and 2) to qualitate and quantify the discomfort from atrial defibrillation shocks delivered by a clinically relevant method. BACKGROUND: Biatrial shocks result in the lowest thresholds for transvenous atrial defibrillation, but the optimal right atrial and coronary sinus electrode locations for defibrillation efficacy in humans have not been defined. METHODS: Twenty-eight patients (17 men, 11 women) with chronic atrial fibrillation (AF) (lasting > or = 1 month) were studied. Transvenous atrial defibrillation was performed by delivering R wave-synchronized biphasic shocks with incremental shock levels (from 180 to 400 V in steps of 40 V). Different electrode location combinations were used and tested randomly: the anterolateral, inferomedial right atrium or high right atrial appendage to the distal coronary sinus. Defibrillation thresholds were defined in duplicate by using the step-up protocol. Pain perception of shock delivery was assessed by using a purpose-designed questionnaire; sedation was given when the shock level was unacceptable (tolerability threshold). RESULTS: Sinus rhythm was restored in 26 of 28 patients by using at least one of the right atrial electrode locations tested. The conversion rate with the anterolateral right atrial location (21 [81%] of 26) was higher than that with the inferomedial right atrial location (8 [50%] of 16, p < 0.05) but similar to that with the high right atrial appendage location (16 [89%] of 18, p > 0.05). The mean defibrillation thresholds for the high right atrial appendage, anterolateral right atrium and inferomedial right atrium were all significantly different with respect to energy (3.9 +/- 1.8 J vs. 4.6 +/- 1.8 J vs. 6.0 +/- 1.7 J, respectively, p < 0.05) and voltage (317 +/- 77 V vs. 348 +/- 70 V vs. 396 +/- 66 V, respectively, p < 0.05). Patients tolerated a mean of 3.4 +/- 2 shocks with a tolerability threshold of 255 +/- 60 V, 2.5 +/- 1.3 J. CONCLUSIONS: Low energy transvenous defibrillation with an implantable defibrillation lead system is an effective treatment for AF. Most patients can tolerate two to three shocks, and, when the starting shock level (180 V) is close to the defibrillation threshold, they can tolerate on average a shock level of 260 V without sedation. Electrodes should be positioned in the distal coronary sinus and in the high right atrial appendage to achieve the lowest defibrillation threshold, although other locations may be suitable for certain patients.     

Tubular-wire dual electrode for detection of thiols and disulfides by capillary electrophoresis/electrochemistry

A new dual-electrode detector for capillary electrophoresis is described. The detector consists of an integrated gold tubular electrode as the generator electrode and a gold wire electrode for detection. The detector configuration, including electrode size and position, has been optimized in terms of detection sensitivity and separation efficiency. After amalgamation of the dual electrode with mercury, the capillary electrophoresis/electrochemistry system was employed for simultaneous detection of thiols and disulfides. The response of cystine was found to be linear from 1 microM to 1 mM with a LOD of 0.5 microM (S/N = 3) and sensitivity of 60 pA/microM. The detection limits represent 200-fold improvement over previously reported dual-electrode designs for the detection of disulfides. The use of this detector for identification of thiol- and disulfide-containing peptides was demonstrated with a tryptic digest of ribonuclease A.     

Pantoprazole-based dual and triple therapy for the eradication of Helicobacter pylori infection: a randomized controlled trial

BACKGROUND/AIMS: The eradication of Helicobacter pylori (Hp) infection in duodenal ulcer and dyspepsia has been achieved using various therapy regimens. The efficacy of protein pump inhibitor pantoprazole as part of these regimens has not been widely studied. METHODOLOGY: During a prospective randomized trial, 250 Hp positive patients with either duodenal ulcer, erosive bulbitis, or gastritis and dyspepsia were treated using 14 days of therapy 1) pantoprazole 40 mg daily and clarithromycin 500 mg b.i.d. (PC), 2) pantoprazole 40 mg daily and clarithromycin 500 mg b.i.d. plus amoxicillin 1 g b.i.d. (PCA), or 3) bismuth subcitrate 120 mg t.i.d., roxithromycin 150 mg b.i.d., metronidazole 250 mg b.i.d. plus ranitidin 300 mg (BRMR). Hp status was assessed on 3 tests at the inclusion (2-specimen rapid urease test, 2-specimen histology, serology) and 2 tests (2-specimen rapid urease test, 2-specimen histology) 4 weeks after the end of the treatment. RESULTS: The entry criteria was fulfilled in 250 patients, of whom 13 missed the control endoscopy. The treatment had to be discontinued for adverse effects in 8 (10%) BRMR patients, and 1 (1%) PCA patients. Compliance was 100% in the PC group. All ulcers were healed at the end of the study with one exception in the BRMR group. The best eradication rate of Hp was shown by the PCA group with 94.8% (n = 73/77) followed by the PC group with 82.5% (n = 66/80) and finally the BRMR with 67.6% (n = 48/71)-PCA:BRMR - p < 0.001; PC:BRMR-p < 0.001; PCA:PC-p < 0.05. CONCLUSION: This study showed that triple therapy using PPI pantoprazole combined with antibiotics clarithromycin and amoxicillin was very effective in the eradication of Hp and treatment of duodenal ulcer with rare side effects. The dual pantoprazole and clarithromycin therapy had the highest rate of patient compliance, but is less effective than triple therapy. The combination of ranitidin with bismuth based triple therapy had the highest number of adverse events and the lowest rate of Hp eradication and therefore, should not be recommended.     

Postshock sensing performance in transvenous defibrillation lead systems: analysis of detection and redetection of ventricular fibrillation

INTRODUCTION: The sensing performance of transvenous lead systems may be adversely affected by the delivery of high-energy shocks. This may be due to the proximity of the sensing and energy-delivery electrodes on transvenous leads. METHODS AND RESULTS: The time required for detection of ventricular fibrillation and redetection after a failed first shock was compared in 93 patients with five different lead system-pulse generator combinations: Cadence--Endotak 60 series, Ventak P--Endotak 60 series, Jewel--Transvene, Cadence--TVL, and Cadence--Transvene. A total of 418 successful and 204 failed first shocks were delivered during induced ventricular fibrillation. Redetection times (RED) were consistently shorter than detection times (DET) in the Jewel-Transvene (RED minus DET: -1.9 +/- 0.8 sec, P < 0.0001), the Cadence-TVL (-1.6 +/- 1.0 sec, P < 0.0001), and the Cadence-Transvene combinations (-2.0 +/- 0.9 sec, P < 0.0004). Redetection times were not significantly different than detection times in the Cadence-Endotak combination (0.9 +/- 3.1 sec; P = 0.09). Redetection times were significantly longer than detection times in the Ventak-Endotak combination (1.2 +/- 2.3 sec; P = 0.034). Prolonged individual redetection episodes (> 8.2 sec) were observed in the Cadence-Endotak (7 [10%] of 73 episodes) and the Ventak-Endotak (4 [10%] of 39 episodes), but not in the Jewel-Transvene, the Cadence-TVL, and the Cadence-Transvene combinations. CONCLUSIONS: Redetection of ventricular fibrillation may be delayed in some transvenous lead-pulse generator combinations. Successful redetection of ventricular fibrillation following a failed first shock should be demonstrated prior to hospital discharge of patients with implantable defibrillators.     

A prospective randomized trial comparing the use of omeprazole-based dual and triple therapy for eradication of Helicobacter pylori

BACKGROUND: Controversy surrounds the optimal composition, dosage, and duration of therapies for eradication of Helicobacter pylori. We prospectively compared omeprazole-based dual and triple therapies in the eradication of H. pylori in a randomized manner. METHODS: Between June 1995 and March 1997, 1000 consecutive patients with acid-peptic disease associated with H. pylori infection (duodenal ulcer, 388 patients, gastric ulcer, 179 patients; duodenitis, 173 patients; gastritis, 260 patients) were prospectively recruited. They were randomized to either a 2-wk (OA) course of omeprazole 20 mg and amoxicillin 1 g, both given twice daily, or treatment for 1 wk (OCM) with omeprazole 20 mg once daily, clarithromycin 500 mg twice daily, and metronidazole 400 mg twice daily. RESULTS: The age of these 1000 patients ranged from 16 to 90 yr, with a mean of 54.9 yr. Side effects occurred in 29.6% (95% confidence interval [CI] 25.6-33.8%) and 10.6% (95% CI 8.0-13.6%) of patients taking OCM and OA, respectively (p < 0.0001). Apart from taste disturbance, however, there were no significant differences in the incidences of side effects between the two groups. One patient in the OA group and four patients of the OCM group could not tolerate the medications, and therefore did not complete treatment (p = 0.37). Seven and 13 patients in the OA and OCM groups, respectively, refused a second endoscopy (p = 0.25). The remaining 975 patients underwent a second endoscopy. Positive endoscopic findings were significantly more common in the OA group (51/492; 10.4%; 95% CI 7.8-13.4%) than in the OCM group (25/483; 5.2%; 95% CI 3.4-7.5%) in the per-protocol (PP) analysis (p = 0.004). On intent-to-treat (ITT) analysis, the overall eradication rates in the OA and OCM groups were 73.6% (95% CI 69.5-77.4%) and 92% (95% CI 89.3-94.2%), respectively (p < 0.0001). On PP analysis, the corresponding rates were 74.8% (95% CI 70.7-78.6%) and 95.2% (95% CI 92.9-97.0%), respectively (p < 0.0001). CONCLUSIONS: A course of omeprazole, clarithromycin, and metronidazole for 1 wk is a safe, well-tolerated, efficacious, and cost-effective treatment for H. pylori infection.     

Preliminary animal and clinical experiences using an electromechanical endocardial mapping procedure to distinguish infarcted from healthy myocardium

BACKGROUND: A catheter-based left ventricular (LV) endocardial mapping procedure using electromagnetic field energy for positioning of the catheter tip was designed to acquire simultaneous measurements of endocardial voltage potentials and myocardial contractility. We investigated such a mapping system to distinguish between infarcted and normal myocardium in an animal infarction model and in patients with coronary artery disease. METHODS AND RESULTS: Measurements of LV endocardial unipolar (UP) and bipolar (BP) voltages and local endocardial shortening were derived from dogs at baseline (n=12), at 24 hours (n=6), and at 3 weeks (n=6) after occlusion of the left anterior descending coronary artery. Also, 12 patients with prior myocardial infarction (MI) and 12 control patients underwent the LV endocardial mapping study for assessment of electromechanical function in infarcted versus healthy myocardial regions. In the canine model, a significant decrease in voltage potentials was noted in the MI zone at 24 hours (UP, 42. 8+/-9.6 to 29.1+/-12.2 mV, P=0.007; BP, 11.6+/-2.3 to 4.9+/-1.2 mV, P<0.0001) and at 3 weeks (UP, 41.0+/-8.9 to 13.9+/-3.9 mV, P<0.0001; BP, 11.2+/-2.8 to 2.4+/-0.4 mV, P<0.0001). No change in voltage was noted in zones remote from MI. In patients with prior MI, the average voltage was 7.2+/-2.7 mV (UP)/1.4+/-0.7 mV (BP) in MI regions, 17.8+/-4.6 mV (UP)/4.5+/-1.1 mV (BP) in healthy zones remote from MI, and 19.7+/-4.4 mV (UP)/5.8+/-1.0 mV (BP) in control patients without prior MI (P<0.001 for MI values versus remote zones or control patients). In the canine model and patients, local endocardial shortening was significantly impaired in MI zones compared with controls. CONCLUSIONS: These preliminary data suggest that infarcted myocardium could be accurately diagnosed and distinguished from healthy myocardium by a reduction in both electrical voltage and mechanical activity. Such a diagnostic electromechanical mapping study might be clinically useful for accurate assessment of myocardial function and viability.     

Prediction of percent body fat in adult males using dual energy x-ray absorptiometry, skinfolds, and hydrostatic weighing

The purpose of this study was to compare the prediction of percent body fat (%FAT) by dual energy x-ray absorptiometry (DXA), skinfolds (SF), and hydrostatic weighing (HW) in adult males. Subjects were 35 adult male Caucasians (mean +/- SD; age: 39.1 +/- 14.0 yr, height: 180.6 +/- 5.3 cm, weight: 81.0 +/- 11.1 kg). %FAT, determined by HW with residual volume determined via O2 dilution, served as the criterion. DXA %FAT was determined by the Norland XR-26 (XR-26) bone densitometer and by the SF equations of Jackson and Pollock (JP) (1978), and Lohman (LOH) (1981). Criterion referenced validation included analyzing mean (+/- SD) %FAT values using a one-way ANOVA for significance, comparison of mean differences (MD), correlations (r), standard error of estimates (SEE), and total errors (TE). Significant differences were found between means of each method. The r (0.91) and SEE (3.0 %FAT) for DXA compare favorably with the established SF methods of JP and LOH for predicting %FAT; however, DXA demonstrated the largest MD (3.9 %FAT) and TE (5.2 %FAT). Regression analysis yields HW = 0.79* DXA + 0.56. The results do not support earlier research that found no significant difference between HW and DXA %FAT in males. The study suggests the density of the fat-free body (DFFB) is not constant, and that the variation in bone mineral content affects the DFFB, which contributes to the differences between DXA and HW %FAT. We recommend further research to identify inconsistencies between manufacturers of DXA equipment in prediction of %FAT in males.     

Measurement of the left ventricular mass using MRI with automatic determination of the endocardial and epicardial contours

This study describes a method of automatic border detection of the left ventricular endocardium and epicardium associating three methods of segmentation (increase of region, border detection and adaptive threshold), applicable to the evaluation of ventricular mass and volume by magnetic resonance imaging. Despite slight underestimation, the spin-echo sequence used in 9 small pigs provided a value of left ventricular mass close to that observed ex vivo (r = 0.97, SEE = 6.05 g). Clinical validation using a rapid gradient-echo sequence was undertaken and compared with manual border detection carried out by three independent, trained operators. The study population included healthy subjects and patients with global or segmental left ventricular dysfunction with or without ventricular deformation. The correlations between automatic and manual detection were satisfactory both for calculation of left ventricular mass (r = 0.93, SEE = 13 g) and measurement of surfaces (r = 0.91, SEE = 1.4 cm2). The concordance of the two methods was confirmed by the Bland and Altman test. Cardiac magnetic resonance imaging may provide accurate and reproducible measurements of left ventricular mass within acceptable acquisition and image processing times for routine use. Although the clinical value of such a method is accepted both for establishing the prognosis and guiding management, studies of the cost/efficacy ratio should be undertaken to situate magnetic resonance imaging with respect to other non-invasive techniques of investigation of left ventricular function.     

Simultaneous determination of maltose and glucose using a screen-printed electrode system

A screen-printed sensor system consisting of a glucose oxidase (GOD) electrode and an amyloglucosidase/glucose oxidase (A/G) electrode was constructed to determine maltose and glucose simultaneously in a mixture. Sensor construction was optimised so that it contained 20 units of GOD/40 units of amyloglucosidase and 0.2 mM 1,1'-ferrocenedimethanol. These components were deposited onto a screen-printed carbon electrode and an outer membrane was printed from 3.5% hydroxyethyl cellulose (HEC) solution. The optimum pH was 4.8. The linear range of the system was up to 40 mM glucose or 20 mmol/L maltose with coefficients of variation (CVs) ranging from 3.5% to 5.29%. The results obtained by using the enzyme electrode system agreed well with those obtained by the Fehling titration method. When stored dry, especially at 4 degrees C, the enzyme electrodes showed good stability over four months.